Is there any way to modify a queue limit without a reload? I don’t believe a broadcast can as queues are in the scheduling area, so I wondered if there was some other tool that could do this?
No. Broadcast is for making “temporary” changes to upcoming task instances (and can be used to communicate dynamic information between tasks), and Reload is for loading “permanent” changes to the flow.cylc config file (quotes added for fairly obvious reasons).
Is there some reason why you don’t want to do a reload in this case?
I’m still thinking about it. In this case, I wanted to modify a queue limit without waiting an hour or two to be able to deploy an update. I can see situations where a downstream server is having performance problems or something like that, and we want to reduce the throughput for a couple of cycles or a day, so a broadcast type action to modify it with a designated expiry feels nicer for my works environment.
Presumably that’s a limitation imposed by site security restrictions, or something, not Cylc, right?
In principle we could allow direct modification of arbitrary scheduler config settings via a command, but I don’t think it occurred to us before that simply tweaking the config file (and reloading it) would not be allowed.
Broadcast is different because it’s often used to convey dynamic information between tasks, and messing with the workflow config would not be appropriate for that.
Cylc queues can help prevent your workflow from flooding a job host (typically localhost), or overwhelming the Cylc server with submission commands, but they aren’t really intended to manage the workload of job hosts (and they can’t because they are distributed), that’s the function of the job runner.
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